410
FXUS65 KBOI 220254
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
754 PM MST SAT DEC 21 2024
DISCUSSION
TEMPERATURES HAVE DROPPED OFF SLIGHTLY THIS
EVENING AS THE WEAK COLD FRONT PUSHES EAST THIS EVENING. A FEW
STRAY SHOWERS ARE LINGERING OVER THE TREASURE VALLEY, BRINGING
VERY BRIEF PERIODS OF RAIN AND RAIN-SNOW MIX. THESE WILL END BY
10:00PM MST. WINDS WILL BE LIGHT OVERNIGHT, WITH SOME SOUTHEAST
WINDS KICKING UP IN THE MAGIC VALLEY THROUGH THE OVERNIGHT
PERIOD AHEAD OF ANOTHER SYSTEM INCOMING TOMORROW MORNING. SNOW
AMOUNTS WILL BE LIGHT IN THE MOUNTAINS, WITH SNOW LEVELS AROUND
4000-5000 FEET MSL. THERE IS A LOW CHANCE (<15% CHANCE) OF
FREEZING RAIN BRIEFLY NEAR CALDWELL-ONTARIO IN THE MORNING WITH
THE PUSH OF WARM AIR IN THE LATE MORNING. OTHER THAN
TEMPERATURES BEING UPDATED TO REFLECT COOLER TEMPERATURES THIS
EVENING, FORECAST IS ON TRACK.
AVIATION
MAINLY VFR WITH MID/HIGH CLOUDS, EXCEPT MAINLY MVFR/IFR
IN THE MOUNTAINS. LIGHT VALLEY RAIN/MOUNTAIN SNOW ALONG A COLD FRONT
TOMORROW MORNING. IN BETWEEN, SPRINKLES OR FLURRIES ARE LIKELY,
WITH A 20% TO 50% CHANCE OF MEASURABLE PRECIPITATION IN
SHOWERS. SNOW LEVELS 4000-6000 FT MSL. MOUNTAINS FREQUENTLY
OBSCURED. SURFACE WINDS: SE-SW 5-10 KT. WINDS ALOFT AT 10KFT
MSL: SW 20-35 KT THIS EVENING.
KBOI...VFR. RAIN SHOWERS WILL MOVE THROUGH THIS AFTERNOON THROUGH
EARLY EVENING, BUT CIGS SHOULD REMAIN VFR. SURFACE WINDS VARIABLE 6
KT OR LESS, BRIEFLY STRONGER IN SHOWERS.
PREV DISCUSSION
SHORT TERM...TONIGHT THROUGH MONDAY NIGHT...PRECIPITATION
TAPERS OFF THIS EVENING AS THE CURRENT WAVE EXITS EASTWARD.
MOUNTAINS WILL SEE LIGHT ACCUMULATIONS, GENERALLY LESS THAN 3
INCHES. THERE IS A BRIEF BREAK BEFORE THE NEXT UPPER TROUGH
PUSHES INTO THE PAC NW ON SUNDAY. THIS SYSTEM WILL BRING ANOTHER
ROUND OF RAIN AND SNOW, INITIALLY ACROSS SOUTHERN ZONES SUNDAY,
BECOMING MORE WIDESPREAD SUNDAY NIGHT AS THE UPPER TROUGH
TRACKS THROUGH NE OREGON AND W-CENTRAL IDAHO. SNOW LEVELS
ACCOMPANYING THE BULK OF PRECIPITATION SUNDAY NIGHT WILL RANGE
BETWEEN 5-6KFT ACROSS E-CENTRAL OREGON AND THE W-CENTRAL IDAHO
MTNS, AND 6500-7500 FEET ACROSS SE OREGON AND THE SNAKE PLAIN TO
THE ID/NV BORDER. LIQUID AMOUNTS/EQUIVALENTS WILL RANGE FROM
0.05-0.15 INCHES IN THE VALLEYS AND LOWER ELEVATIONS OF SE
OREGON TO 0.25-0.50 INCHES ACROSS THE MOUNTAINS. MOUNTAIN
VALLEYS BELOW 5500 FEET WILL STRUGGLE TO ACCUMULATE A WET 1-2"
OF SNOW, WHILE SITES ABOVE 6000 FEET ARE IN LINE TO SEE 3-6"
LATE SUNDAY THROUGH MONDAY MORNING. IT DRIES OUT MONDAY UNDER A
TRANSITING UPPER RIDGE BUT PRECIPITATION WILL SPREAD BACK INTO
SE OREGON MONDAY NIGHT AS A THIRD WAVE APPROACHES THE PAC NW
COAST. TEMPERATURES WILL REMAIN AROUND 10 DEGREES ABOVE NORMAL
THROUGH MONDAY.
LONG TERM...TUESDAY THROUGH SATURDAY...LONG RANGE MODELS CONTINUE TO
CLUSTER WELL, CONTINUING THE HIGH CONFIDENCE IN THE BASIC PATTERN
CHANGE TO ACTIVE AND VERY WET/SNOWY CONDITIONS. THE NEXT SYSTEM WILL
ARRIVE TUE, THEN ANOTHER THU, A WEAK ONE FRI, AND THE BEGINNING OF A
WHAT LOOKS LIKE AN EXTENDED PERIOD OF PRECIPITATION SATURDAY. SNOW
LEVELS ARE FORECAST TO REMAIN ABOVE VALLEY FLOORS, SO AT THIS TIME WE
ARE NOT PREDICTING ACCUMULATING SNOW FOR PLACES LIKE BOISE OR TWIN
FALLS (MIGHT SEE A FEW FLAKES, BUT NO ACCUMULATION). TEMPERATURES ARE
EXPECTED TO BE ABOVE NORMAL, ESPECIALLY TUE AND SAT (AROUND 10 DEGREES
ABOVE NORMAL), WITH THE INTERVENING DAYS JUST A FEW DEGREES ABOVE
NORMAL. FINALLY, AND IMPORTANTLY, THE POTENTIAL FOR SIGNIFICANT SNOW
ACCUMULATION IN THE MOUNTAINS IS HIGH, WITH 2 TO 4 FEET OF SNOW
CURRENTLY IN THE MODELS OVER THE NEXT 10 DAYS (DEC 21 TO DEC 30).
MCCALL IS EXPECTED TO SEE A MIX OF RAIN AND SNOW, BUT ELEVATIONS ABOVE
6000 FT MSL SHOULD BE ALL OR ALMOST ALL SNOW.
BOI WATCHES/WARNINGS/ADVISORIES
ID...NONE.
OR...NONE.
WWW.WEATHER.GOV/BOISE
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSBOISE
WWW.TWITTER.COM/NWSBOISE
DISCUSSION...SA
AVIATION.....SA
SHORT TERM...DG
LONG TERM....SP
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